Because a conventional PCR method using Joule heating of a reaction solution makes a DC current flow through the reaction solution, the reaction solution is electrolyzed to produce unnecessary gas on the periphery of the electrodes, and produce unnecessary acidic and alkaline solutions. Moreover, because a voltage is applied to both ends of a long channel, a high voltage must be applied to generate necessary Joule heat, causing a large circuit burden.
Therefore, for example, Patent Literature 1 describes a PCR device for which, on an inner surface of a container to carry out polymerase chain reaction (PCR), an electrode pair to be disposed to face each other with a gap along a flow of a reaction solution interposed therebetween, and which applies an AC voltage to the electrode pair to make an AC current flow through the reaction solution, thereby generating Joule heat to control the reaction solution in temperature.
FIG. 6 is a front view of a reaction container of the PCR device described in Patent Literature 1.
As depicted in FIG. 6, the PCR device described in Patent Literature 1 comprises a cover plate 41, an outlet 42, an inlet 43, a channel 44, an electrode pair 45, a channel forming plate 46, and a substrate, and the reaction container is vertically erected. The PCR device described in Patent Literature 1 makes an electric current flow into a reaction solution in a gap between the electrode pair 45, and heats the reaction solution by Joule heat thereof to cause PCR amplification. The reaction solution is, by circulating in the annular channel 44, raised and lowered in temperature to undergo temperature changes of a PCR cycle so as to cause PCR amplification.